Roofing Granules with High Solar Reflectance, Roofing Products with High Solar Reflectance, and Processes for Producing Same

Abstract

Solar reflective roofing granules include a binder and inert mineral particles, with solar reflective particles dispersed in the binder. An agglomeration process preferentially disposes the solar reflective particles at a desired depth within or beneath the surface of the granules.

1 - 14 . (canceled) 
     
     
         15 . Solar reflective roofing granules, each comprising
 (a) a granule body comprising inert mineral particles or ceramic particles bound by an inorganic binder, the granule body having an exterior surface; and   (b) solar reflective particles, the solar reflective particles being adhered to the granule body only at or proximate to the exterior surface of the granule.   
     
     
         16 . Solar reflective roofing granules according to  claim 15  wherein the solar reflective particles are mechanically adhered to the exterior surface of the granule bodies. 
     
     
         17 . Solar reflective roofing granules according to  claim 15  wherein the solar reflective particles are selected from the group consisting of titanium dioxides, metal pigments, titanates, and metal reflective pigments. 
     
     
         18 . Solar reflective roofing granules according to  claim 15  wherein the granule body comprises inert mineral particles. 
     
     
         19 . Solar reflective roofing granules according to  claim 18  wherein the inert mineral particles have an average particle size from about 0.1 micrometers to about 40 micrometers. 
     
     
         20 . Solar reflective roofing granules according to  claim 15  wherein the granule body comprises ceramic particles. 
     
     
         21 . Solar reflective roofing granules according to  claim 15  wherein the binder is selected from the group consisting of silicate, silica, phosphate, titanate, zirconate, and aluminate binders, and mixtures thereof. 
     
     
         22 . Solar reflective roofing granules according to  claim 21  wherein the binder further comprises aluminosilicate or kaolin clay. 
     
     
         23 . Solar reflective roofing granules according to  claim 15 , wherein each granule further comprises a coloring pigment. 
     
     
         24 . Solar reflective roofing granules according to  claim 15  having a solar reflectance of at least about 60%. 
     
     
         25 . A roofing product comprising solar reflective roofing granules according to  claim 15 . 
     
     
         26 . The roofing product according to  claim 25 , wherein the roofing product is in the form of a shingle comprising a bituminous substrate having the solar reflective roofing granules adhered to a surface thereof. 
     
     
         27 . Solar reflective roofing granules, each granule comprising a granule body comprising ceramic particles and solar reflective particles homogeneously dispersed with one another and bound by an inorganic binder, the granule body having an exterior surface, a plurality of the solar reflective particles being located at or proximate to the exterior surface of the granule. 
     
     
         28 . Solar reflective roofing granules according to  claim 27  wherein the solar reflective particles are selected from the group consisting of titanium dioxides, metal pigments, titanates, and metal reflective pigments. 
     
     
         29 . Solar reflective roofing granules according to  claim 27  wherein the binder is selected from the group consisting of silicate, silica, phosphate, titanate, zirconate, and aluminate binders, and mixtures thereof. 
     
     
         30 . Solar reflective roofing granules according to  claim 29  wherein the binder further comprises an inorganic material selected from the group consisting of aluminosilicate and kaolin clay. 
     
     
         31 . Solar reflective roofing granules according to  claim 27  having a solar reflectance of at least about 60%. 
     
     
         32 . Solar reflective roofing granules according to  claim 27 , wherein each granule body further comprises a coloring pigment bound together with the ceramic particles and the solar reflective particles by the binder. 
     
     
         33 . A roofing product comprising solar reflective roofing granules according to  claim 27 . 
     
     
         34 . The roofing product according to  claim 33 , wherein the roofing product is in the form of a shingle comprising a bituminous substrate having the solar reflective roofing granules adhered to a surface thereof.